The invention relates generally to hydrophones and more particularly to shock-hardened hydrophones.
Many underwater applications such as geophysical prospecting and submarine warfare require a hydrophone that is capable of functioning after being exposed to an explosive shock. Shock-hardening is generally achieved in a hydrophone utilizing piezoelectric transducers by mechanically pre-loading the transducers. This pre-loading prevents the transducer from shattering due to forces present in a high shock environment. Existing shock-hardened hydrophones utilize complicated methods, such as winding with a fiber glass layer, to achieve the required pre-load.
Additional desirable hydrophone qualities include ease of fabrication for reducing cost and low output-impedance for driving long cables. Existing hydrophones utilize piezoelectric sensors with foil electrodes mounted thereon, thus requiring that input wires from an amplifier be soldered to small protruding foil tabs on the foil electrodes. This soldering is a time-consuming, expensive operation.
Additionally, transformers are often utilized to provide low output-impedance in existing hydrophones. However, the transformers are neither inexpensive nor reliable.